Vehicles are generally equipped with audio devices that play an audio sound in a cabin. JP2776092B and JP1993-085288A disclose audio devices that perform localization of an audio sound so that a person(s) on board is able to hear the audio sound from a given position in a cabin.
Meanwhile, vehicles which are focused on that enjoyment of traveling, such as sports cars, are required to actively cause person(s) on board, especially a vehicle driver, to hear (listen to) an engine sound. That is, since the engine sound is a good indication of a vehicle state, it becomes an extremely important element in the enjoyment of traveling.
When the audio device is operated to play an audio sound in the cabin, the engine sound may be disturbed by the audio sound and becomes hard to hear from time to time. If the operation of the audio device is stopped to facilitate the hearing of the engine sound, the audio sound cannot be enjoyed at all and this is not suitable.